The present invention relates to the management of computer networks, and is primarily concerned with the identification of network components by a network management application.
In a computer network where numerous components are connected together, network management is carried out by a network management system which is a programme resident in one or more of the servers or “platforms”, and which can communicate with the other components of the system. The tasks of the network management system include routing and managing traffic flows on the network, identifying machines connected to the network, and identifying replaceable parts fitted to machines (platforms) connected to the network.
The network management application typically uses the SNMP protocol for communicating with machines and other entities on the network. Each network component incorporates a processor running a programme referred to as an “agent” which organises the receiving of requests for data sent by the network management application, and manages the preparation and sending of responses to those requests over the network to the network management application. Each network component also has associated with it a memory containing data specific to that component, such as the manufacturer's part number, serial number, etc. This memory is typically in the form of a PROM, and is called the platform ID PROM when associated with a network platform, and a “FRU ID PROM” when it is associated with a field replaceable unit or “FRU”.
Items of Information which may be required by the network management application are each identified by an “Object Identifier”. An object identifier is a number constructed from a sequence of sub-numbers separated by dots. Typically there may be up to 128 sub-numbers and each sub-number may contain up to 32 binary digits. Object identifiers are organised on a tree structure, and each object identifier has a text equivalent for ease of interpretation by the user. One such object identifier is referred to as “SysObjectID”, and a request for this object identifier is in effect a request for a network component to identify itself, the “SysObjectID” object identifier relating to information on the make, model, type, etc. of platform component. Another object identifier is “entPhysicalVendorType”, and this object identifier relates to the identity of a “field replaceable unit” or “FRU” mounted within a platform of the network.
An essential adjunct to the network management application is the “Management Information Base” or MIB. In the MIB are stored correlations between the textual representation of each object identifier, and its number sequence. As has been previously stated, each object identifier corresponds to a piece of information relating to the network or to a component of the network. A network management application may have several MIBs associated with it, correlating specific items of information with their Object Identifier.
The “SysObjectID” object identifier is devoted to the identification of pieces of equipment, or platforms, which form the network, and each equipment manufacturer will provide an MIB listing all of his platforms and the information corresponding to each “SysObjectID” object identifier. Similarly, each FRU of a manufacturer will have its corresponding “entPhysicalVendorType” object identifier listed in a MIB, possibly the same MIB as lists the platform object identifiers. Each manufacturer has a central listing to avoid duplication of object identifiers, so that object identifiers relating to different characteristics of the same piece of equipment, or to characteristics of different items of equipment, are not described using the same numerical sequence.
In a network environment, it is common for one or more platforms (for example servers) connected to the network to have Field-Replaceable-Units or “FRUs” in the form of electronic sub-systems which can be mounted to the platform. A platform may have a number of “slots”, into each of which a FRU can be mounted. Each FRU will have identifying data associated with it, usually held in an ID PROM attached to the FRU, containing identifying information such as the manufacturer's name, the vendor's name, a part number, type number, and a date of manufacture.
Current practice is for the agent to have hard-coded data, for example in the form of a table, correlating the identities of FRUs mountable to the platform with their respective “entPhysicalVendorType” object identifiers. This enables the agent, when asked to identify a FRU mounted to the platform, to interrogate the FRU to get its identity data, and then to look up the corresponding “entPhysicalVendorType” object identifier from the table stored in the agent programme. The object identifier can then be sent to the network management application. The data in the table is stored at the time of release of the platform, and is not easily updatable.
A problem arises for the network management system if the agent running on the processor of the platform, or the MIB stored in the network management application which stores details of the network components, is of an earlier release date than a FRU mounted in the platform of the network. For example, a newly-released FRU may be mounted in a network platform which is some months or years old. In such a case, when the network management application requests the agent in the platform to identify the FRU mounted in a particular slot of the platform by supplying its “entPhysicalVendorType” object identifier, the agent may retrieve identity information from the FRU ID prom, but may not be able to supply an object identifier to the network management application, because the agent's table does not include an object identifier corresponding to that data identity information. This difficulty is only overcome by the simultaneous updating of agent programs in existing networks with each new equipment release, as well as updating of the MIB files held by the network management system. This constant revision of MIB files and agents is costly and requires extensive use of human and machine resources.